1. Field of the Invention
The present invention relates to a magnetic resonance imaging apparatus and a scanning-condition setting method for reconstructing an image by irradiating a subject with a Radio Frequency (RF) wave based on scanning conditions including a plurality of scanning parameters, and detecting a magnetic resonance signal generated from the subject in accordance with the RF wave. Particularly the present invention relates to setting of scanning conditions to be carried out for a scan.
2. Description of the Related Art
Conventionally, a magnetic resonance imaging apparatus collects data indicating the inside of the body of a subject by using a magnetic resonance phenomenon based on scanning conditions specified by an operator, and reconstructs an image from the collected data. The scanning conditions specified by the operator include a number of scanning parameters, for example, a repetition time (TR), an echo time (TE), the number of slices, a slice thickness, and a Field Of View (FOV).
The variety of those scanning parameters is quite wide (sometimes, there are approximately 700 parameters in some cases), and not a few parameters are dependent on one another such that the parameter value of one scanning parameter is restricted by the parameter value of another scanning parameter. For this reason, a conventional magnetic resonance imaging apparatus requires enormous efforts for setting scanning conditions, and various technologies for facilitating setting of scanning conditions have been invented.
For example, JP-A 2006-255189 (KOKAI) discloses a technology according to which an order of precedence of scanning parameters are set in advance; then after the parameter value of a scanning parameter of the highest priority is input, allowable ranges of parameter values of the other scanning parameters are calculated not to change the input parameter value; and an operator sets parameter values within the calculated allowable ranges, so that the operator efficiently sets scanning conditions while checking a dependence relationship between the scanning parameters.
The technology is effective when setting scanning parameters one by one. However, because the variety of scanning parameters used by a magnetic resonance imaging apparatus is considerably wide as described above, there are user demands for simultaneously setting a plurality of scanning parameters.
To respond to the demands, conventionally a technology for simultaneously setting a plurality of scanning parameters has been also invented. FIGS. 10 and 11 are schematic diagrams for explaining an example of a conventional technology for simultaneously setting a plurality of scanning parameters.
For example, as shown in FIG. 10, there is a technology according to which when a “coordination mode” is selected in advance by an operator on a scanning-condition setting screen for setting scanning parameters, upon changing the parameter value of a specific parameter that is usually often set, the parameter value of another relevant scanning parameter is automatically changed. According to the example in the figure, when the parameter value of “PE-FOV” is changed, the parameter value of “RO-FOV” that is relevant to “PE-FOV” is automatically changed to the same value as that of “PE-FOV”.
Alternatively, as shown in FIG. 11, there is a technology according to which when “plan duplicator” is selected by the operator on the same scanning-condition setting screen as that in FIG. 10, a list of scanning protocols that are already set (the list of “Locator AX/CO” to “FLEIR AX” shown in the figure) is displayed, and a parameter value of a scanning parameter is copied from scanning conditions of a scanning protocol selected from the list, and set as a new scanning condition. A scanning parameter to be copied is selected in advance by the operator from among specific scanning parameters displayed on a certain screen (for example, a screen shown in the lower part of the figure).
However, when setting scanning conditions as described above, there is a demand for simultaneously setting arbitrarily selected scanning parameters, for example, in accordance with a scan aim, not limited to specific scanning parameters (for example, “PE-FOV” and “RO-FOV”). According to the conventional technologies described above, to respond to the demand, there is a problem such that a unit for setting scanning conditions is each scanning parameter, or even when a plurality of scanning parameters can be simultaneously set, scanning parameters that can be set are limited to specific parameters, so that arbitrarily selected scanning parameters cannot be simultaneously set.